The present invention is directed to a handling apparatus employed to handle panel like articles, such as the main body panel components which are to be subsequently assembled as a unitized vehicle body, to successively advance the panels to each of a series of work stations on a production line basis.
In the assembly of a unitized body, the first step in the assembly or framing of the body brings together at the first framing station on the body assembly production line various major panels, locates the panels in assembled relationship with each other and, while the panels are so located, robotic welders weld the panels to each other to form a vehicle body shell. Typically, this first step in the framing process will involve a vehicle body floor panel, right and left hand side panels, a fire wall panel and a roof panel or roof header members extending transversely between the upper portions of the body side panels. Once the panels are assembled to each other at the first framing station, access to portions of the individual panels at the interior of the body shell becomes restricted, and it is thus conventional practice to perform several preassembly steps on the individual panels before they are advanced to the framing station. In the case of a body side panel, for example, the panel is initially stamped from sheet metal, and is then advanced through a series of work stations where additional parts, such as door latch and hinge reinforcements, mounting brackets, stiffeners, etc., are welded in place on the sheet metal stamping.
In a commonly owned copending application, filed Jan. 12, 1990, now U.S. Pat. No. 4,991,707 there is disclosed a conveyor for conveying a body side panel to a series of work stations where the preframing operations referred to above are performed on the body side panel. The conveying system of the aforementioned application, now U.S. Pat. No. 4,991,707, includes a carrier mounted for movement along an elevated horizontal path extending past a series of work stations. A generally rectangular open support frame is mounted along one edge upon the carrier for pivotal movement relative to the carrier about a horizontal axis parallel to the conveying path. While the carrier is being advanced from one work station to the next, the support frame is maintained in a horizontal elevated position well clear of the plant floor. The body side panel, during this transfer step, is held against the underside of the support frame by what will be referred to generally as a plurality of clamps. Upon arrival at a work station, the carrier is stopped and a manipulator associated with the conveyor pivots the support frame downwardly to a vertically inclined or vertical position relative to the carrier to locate the body side panel in adjacent relationship with a stationary panel receiving work frame at the work station. The panel is transferred to the stationary work frame and the support frame is then pivoted back upwardly to its horizontal position clear of the panel on the work frame. After the work operations have been performed on the panel while the panel is held on the stationary work frame, the support frame is again pivoted downwardly, the panel is reclamped to the support frame, and the support frame with the panel is then pivoted back upwardly to its horizontal position relative to the carrier for advancement to the next work station.
In the body side panel conveying system described above, the irregular shape of the body side panel requires that several individual releasable clamps be located upon the support frame to positively retain the side panel upon the frame during transit from one stationary panel receiving frame to the next. To facilitate transfer of the side panel back and forth between the support frame and stationary work frame, it is essential that all of the several clamps be simultaneously released or engaged. Because of the length of the conveying path and the requirement of pivotal movement of the support frame relative to its carrier, it is impractical to connect pneumatic supply lines or electrical cables to the individual support frames to pneumatically or electrically actuate the clamping devices. The clamps, and the clamp actuating devices must thus be so designed that the clamps are positively retained in their clamping position during transfer movement of the support frame and positively retained in their unclamped configuration while the support frame is separated from the panel at the work station.
The present invention is especially directed to a clamping system in which a plurality of individual clamping or positioning devices carried upon the support frame may be simultaneously shifted between their respective panel clamping or retaining positions and respective released or retracted positions and in which the clamps or locators are positively retained in either of their actuated or released positions.